Shock resistant electrical relays



Aug. 25, 1964 J. A. RUSS SHOCK RESISTANT ELECTRICAL RELAYS Filed m 26, 1961 United States, Patent 3,146,382 SHUCK RESISTANT ELECTRKCAL RELAYS John A. Russ, Perm Hills Township, Allegheny County, Pa'., assignor to Westinghouse Air Brake Company, Wilmerding, Pa, a corporation of Pennsylvania Filed May 26, 1961, Ser. No. 113,034 2 Claims. (Cl. 317-497) This invention relates generally to electrical relays, and more particularly to electrical relays having a mounting arrangement for rotary armatures capable of withstanding severe vibration environments.

A related relay of the type under consideration in the present application is disclosed in US. Patent No. 2,775,- 666, granted December 25, 1956, to B. Lazich for Electrical Relays. In brief, the relay described in the abovementioned patent comprises a rotary armature mounted on a shaft in such a way that the armature is acted upon to rotate to either of two positions in accordance with whether the relay is or is not energized. The shaft is provided with a bearing member mounted centrally in a header or closure disc which seals one end of the relay when attached to the relay shell. Electrical relays constructed in accordance with the arrangement in the patent are excellently adapted to withstand under operating conditions all of the shocks and vibrations to which they may be subjected. In view, however, of the vast number of operations that the relay is capable of performing, there exists the possibility that the precision mounting of the bearing member in the header may be disturbed, eventually causing the undesirable appearance of deviations in alignment of the rotary parts.

An object of the present invention is the provision of a new and improved electrical relay having high vibration and shock resistant characteristics.

Another object of this invention is the provision of an improved relay having an armature mounting arrangement able to withstand the exacting requirements to which the relay is subjected.

A further object is to provide an improved and novel relay of simple and rugged construction, economically and easily manufactured, compact in size, and reliable in operation.

Still a further object of my invention is the provision of a novel shock resistant relay in which several precision assembly operations heretofore required in prior art relays of the rotary armature type are eliminated.

An electrical relay illustrating features in accordance with the present invention may include a rotatable armature mounted on a shaft supported at one end on a hearing with the armature being engaged by a resilient member for maintaining the armature in a desired attitude during vibration or shock imparted to the relay by environmental forces. I

A complete understanding of the invention and an introduction to other objects and features not specifically mentioned may be had from the following detailed description of a specific embodiment thereof when read in conjunction with the appended drawingsQwherein:

FIG. 1 is a sectional view in elevation of a preferred embodiment of the invention; and

FIG. 2 is a sectional view taken substantially on the lines IIII of FIG. 1.

Referring to the drawings, wherein like reference characters designate like or corresponding parts throughout the views, there is shown in FIG. 1 an outer shell or housing consisting of a tube or cylinder of magnetic material cut to the desired length preferably from a welded tube of suitable diameter having predetermined magnetic characteristics. Tube 10 includes at its lower end an inwardly extending annular portion 10a which may be formed by punching the tube centrally along its longitudi- 3,146,382 Patented Aug. 25, 1964 nal axis. The relay is provided with a central core 12, likewise of magnetic material, pressed into the portion 10a or mounted in any similar manner which rigidly anchors the core.

' The operating coil 14 for the relay is made by winding wire on a spool 16 made of suitable insulating material, with the wire leads 18 and 20 (only one being shown in FIG. 1) projecting from one end of the spool as shown, to facilitate the further assembly of the relay. The coil 14 is inserted in the tube 10 in such a manner that core 12 projects upwardly through spool 16, as shown in the drawings, and with the projecting coil leads adapted to pass through suitable coil lead tubes (not shown) in the header, in the usual manner.

With the coil in its proper position, a coil retaining member or plate 22, which may be punched from a sheet of suitable non-magnetic material, is inserted in the shell as shown, over the end of the spool. This coil retaining plate 22 serves to hold the coil in its proper position against the base of the tube 10 in such a way to afford access to the coil leads. A pole ring 24 (FIGS. 1 and 2), of suitable magnetic material, is axially disposed within the shell and rests against the upper surface of coil retaining plate 22. Integrally formed on the pole ring, such as by casting, are symmetrical and diametrically opposite pairs of pole pieces 24a each of which presents a magnetic contact surface to an armature 26, which contact surfaces, relative to a radial line originating from the axis of the shell, make an angle of approximately 45 degrees. The pole ring 24 is first rigidly attached to the coil retaining plate 22 and this joint assembly is then fixed to the inner wall of the tube 10 by, for example, spot welding or brazing. Thus, when this assembly of the two plates 22 and 24 is inserted in the tube it may be rotated to the required relation to the coil leads, and subsequently the pole ring is attached to the tube.

As shown in the drawings, and particularly with reference to FIG. 2, the armature 26 comprises a central hub portion with four outwardly extending arms or projections 26a equidistantly spaced on the hub. The plane of the magnetic contact surfaces of the armature arms 26a are oifset from a radial line extending from the hub by such a distance that when the armature is attracted toward the pole pieces 24a, the surfaces of the arms and the surfaces of the pole pieces are in substantially parallel relation. Forming the armature 26 and pole pieces 24a with surfaces which lie in planes in diagonal relation to lines radially extending from the axis of the relay constitutes a greater area for magnetic contact, a smaller air gap between these elements for the same amount of travel, and a reduction in leakage flux which normally escapes between the armature and the periphery of the pole ring 24. It should be understood however, that the number and arrangement of the armature arms 26a is not limited to that shown, but the armature 26 may be constructed to have any suitable number of arms, cooperating with a like number of pole pieces, provided that the arrangement is symmetrical with respect to the axis of the shell. It will be noticed that the hub of armature 26 is counterbored to receive the upper portion of the core 12, which is reduced in diameter from the main central portion of core 12. Such an arrangement provides an air gap between the core and the armature which has sufficient area to afford a relatively low reluctance to the magnetic flux flowing between the armature and the core.

The relay under consideration in the present case is of the nature of that generally disclosed in Patent No. 2,775,666 as previously stated, and the description herein above has been directed essentially to the features of the patented relay. In my instant invention, however, the armature 26 is attached rigidly to a shaft 28 to permit rotation of the armature in response to energization of coil 14. Shaft 28 is arranged to rotate on a spherical member 30 placed at the base of an aperture or recess 12a formed in the upper portion of the core, the member 30 thus supporting the shaft. In an alternate arrangement, a bushinginsert (not shown) first may be lodged rigidly in aperture 12a, as, for example, by being press fitted therein, with the member 30 then being disposed to abut against the bushing insert.

The other end of shaft 28 is slightly reduced in diameter and extends with clearance internally of a resilient member herein shown, for example, as a coil spring 32. Spring 32 is compressed between the hub of armature 26 and the underside of a header or closure disc 34 which closes the one end of the relay when attached to tube 10, in the manner shown. A spider or contact operating member 36 of suitable material capable of withstanding shock and extreme temperature changes includes inwardly extending portions 36a (FIG. 2) which overlap the outwardly extending arms 26a ofthe armature. Spider 36. is fixed to the armature 26, for example, as by welding; in the present embodiment the attachment is made at the point where the inwardly extending portions 36a of the spider overlap the armature arms 26a. Suitable contact actuating posts 38 including insulating beads 40- mounted thereon are symmetrically arranged in radial fashion on the spider 36. Extending through the header 34 so as to provide connections with external circuits are terminal posts 42 and 44, only one of each being shown for purposes of simplification. Post 42 is provided with a resilient movable contact member 48 whereas post 44 terminates in a fixed contact member 50. As a result of the armature being attracted to the pole pieces 24a when the coil 14 is energized, each contact member 48 is moved into engagement with its associated fixed contact member 50 to complete circuit connections in the conventional manner. Movement of the armature 26 from its actuated position to its rest position when the coil 14 is subsequently deenergized provides a high degree of immunity to shock and vibration, since the bearing cup in the header required in the known relay art as exemplified in Patent No. 2,775,666 is eliminated. It can be seen that a particular relay embodying the invention has the characteristics of low cost of production, facility of mounting of the header, and protection to a high degree against harmful translational movement of the armature assembly.

It Will be appreciated that air in the interior of the relay may be exhausted by conventional means during production, and I have shown a passage 46 in the core 12 which may connect with the exterior of the relay, and in the conventional manner, not shown, with a pipeconnection to an exhaust manifold. The air exhausted from. the interior of the relay is replaced in general practice by. a suitable gas or gas mixture admitted through the passage 46. Thereafter in the usual manner, the passage 46 may be sealed by the action of a suitable sealing plug (not shown) attached to the base of the core in the conventional manner.

Although I have herein shown and described only one form of electrical relay embodying my invention, it is to be understood that various changes and modifications may be made therein within the scope of the appended claims is accomplished by the spring action of contact members 48. In addition, if desired, suitable biasing means, such as permanent magnets, may be provided as an additional force assisting the armature to return to its rest position.

When the above described assembly is closed by the header 34, the spring 32 exerts a compressive force against the armature 26 coincident with the axis of the shaft 28. This force biases the rotary armature assembly against the spherical member 30 and is determined by the characteristics of the spring and the extent it is compressed from its free length. Thus, in a structure embodying the invention any possible translational movement of the armature assembly during rotation is essentially eliminated or held to a negligible minimum, thereby enhancing the performance of the relay in extreme vibrational environments or in other environmental circumstances which tend to cause the armature assembly to operate in more than one plane. Such a construction has proven eminently satisfactory since corresponding rotary movement of the insulated beads is also'limited to a single plane. This restriction to movement in one plane enables operation of the relay withoutdisfiguration of the beads 40 which precludes the formation of particles that might otherwise occur if spiral movement of the movable contact members were permitted. An appreciable advantage which follows from maintaining sufficient axial compression against the armature is the prevention of contamination by such particles that could possibly cause undesirable electrical characteristics. Also it will be apparent that the arrangement without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim is:

1. In a relay having spaced pole pieces energized by a coil and positioned to receive an armature axially there-. between; a shaft, an armature fixed to the shaft inter mediate its ends and positioned for rotation between the spaced pole pieces, bearing means in tangential contact with one end of the shaft for supporting the shaft for rotation, and means in biasing contact with the armature adjacent the other end of the shaft for resiliently urging the shaft against the bearing means.

2. A relay comprising a shell of magnetic material having a closed end and an open end, a core of magnetic material coaxially disposed in said shell and having an axial recess facing the open end of saidshell, a bearing member in said recess, a shaft rotatively mounted at one end thereof on said bearing member and in tangential contact therewith, said shaft projecting outwardly of said recess, an armature fixed on said shaft, electromagnetic means for operating said armature, a header adjacent the open end of said shell for closing said open end, the shaft other end terminating between the armature and; the header, and means mounted on the shaft other endand interposed between said header and said armature for resiliently urging said shaft toward said bearing member whereby said means maintains a firm contact between the shaft and the bearing member and fixes the rotation of the armature in one plane.

References Cited in the file of this patent UNITED STATES PATENTS 1,700,314 Hartwig Jan. 29, 1929 2,473,598 Leland n June 21, 1949 2,531,905 Carpenter, Nov. 28, 1 950 2,749,403 Herman et al. June 5, 1956 2,775,666 Lazich Dec. 25, 1956 2,824,189 Zimmer Feb. 18, 1958 2,833,508 Bydalek et a1 May 6 1958 2,950,424 Smith et a1 Aug. 23, 1960 7 3,036,176, Kenyon et a1, May 22 1962 

1. IN A RELAY HAVING SPACED POLE PIECES ENERGIZED BY A COIL AND POSITIONED TO RECEIVE AN ARMATURE AXIALLY THEREBETWEEN; A SHAFT, AN ARMATURE FIXED TO THE SHAFT INTERMEDIATE ITS ENDS AND POSITIONED FOR ROTATION BETWEEN THE SPACED POLE PIECES, BEARING MEANS IN TANGENTIAL CONTACT 